Polyquaternary ammonium bisulfites,sulfites and pyrosulfites as developer preservatives

ABSTRACT

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

United States Patent Int. Cl. G03c /30 U.S. Cl. 9666.4 26 Claims ABSTRACT OF THE DISCLOSURE A method of and solution for developing latent images in supported silver halide gelatin layers with the use of an aqueous bath that includes a conventional developing agent or agents and other conventional constituents such as restrainers, anti-foggants, sequestrants, silver halide solvents and gelatin hardeners and which for the developing agent preservative uses a polyquaternary ammonium bisulfite, sulfite or pyrosulfite of the formula where R R R R R R R and R are selected from the class consisting of alkyls having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms, where Z is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers having from- 1 to 3 carbon atoms in each alykylene, where Y is selected from the class consisting of H80 one-half 80:5 and one-half S O and where n is an integer from 0 to 4, the bath also including an alkali in an amount sufiicient to provide the bath with a pH of at least 8.

CROSS REFERENCES TO RELATED APPLICATIONS This application is an improvement over our earlier application, Ser. No. 596,474 filed Nov. 23, 1966, for Processing of Photographic Silver Halide Layers, now abandoned, and our co-pending application, Ser. No. 646,176 filed June 15, 1967, now U.S. Pat. 3,549,370, for Quaternary Ammonium Bisulfites, Sulfites or Pyrosulfites as Developer Preservatives, which is a continuation-inpart of said application Ser. No. 596,474 and was copending therewith.

BACKGROUND OF THE INVENTION (1) Field of the invention A silver halide developing or developing/fixing aqueous bath which includes a conventional developing agent, conventional additives and as a preservative a polyquaternary ammonium bisulfite, sulfite or pyrosulfite.

(2) Description of the prior art Developing baths and monobaths (developer/fixers) for silver halide gelatin layers containing latent images customarily have employed preservatives for preventing oxidation of the developing agent or agents. The preservatives heretofore conventionally employed were alkali metal sulfites, alkali metal bisulfites, hydroxyalkylaminesulfur dioxide addition products and ascorbic acid and its isomers. The alkali metal sulfites and/or bisulfites are Too eifective preservatives but are of limited solubility in water. Concentrates which contained high proportions of hydroxyalkylamine-sulfur dioxide addition products tended to have a high viscosity and, hence, were diificult to pour and measure accurately and to mix smoothly and evenly with diluents such as water. 7

Moreover, some developers containing such prior art preservatives tended to induce a reaction between the preservatives and other constituents of the bath, so that the developer solutions were not highly stable. Specifically, there tended to be a reaction between such prior art preservatives and prior art gelatin hardening agents, viz, aldehydes and dialdehydes.

SUMMARY OF THE INVENTION (1) Purposes of the invention It is an object of the present invention to provide a silver halide photographic processing preservative for developing agents which is not subject to any of the foregoing drawbacks and which can be used to provide liquid developer/fixer concentrates, replenishers and working solutions of all types that are highly stable because it does not tend to react with other constituents of the developers and developer/fixers and the concentrates and replenishers, the preservative even in highly concentrated form being sufliciently non-viscous to pour accurately and with ease and to mix smoothly and readily with diluents such as Water.

It is another object of the present invention to provide for a silver halide photographic developer a developing agent preservative which is at least as efficient in its operation as conventional sulfite preservatives, i.e. which will supply on a weight percentage basis sufficient available sulfur dioxide in Water solution to act as a preservative for the developing agent without requiring the use of an uneconomically large amount of the preservative.

Other objects of the invention in part will be obvious and in part will be pointed out hereinafter.

(2) Brief description of the invention The invention relates to the developing of photographic silver halide layers in an aqueous bath containing a de veloping agent, the said layers being present in the form of silver halide-containing gelatin coating supported on film or paper. Essentially, the invention constitutes developing latent images in such coatings with the bath including as the preservative a polyquaternary ammonium bisulfite, sulfite or pyrosulfite of the formula R; Rs 1: R9 (n+1) where R R R R R R R and R are selected from the class.consisting of alkyls having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms, where Z is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers having from I to 3 carbon atoms in each alkylene, where Y is selected from the class consisting of H one-half SO and one-half S O and where n is an integer from 0 to 4, the bath also including an alkali in an amount suflicient to provide the bath with a pH of at least 8.

The invention accordingly consists in the compositions and series of steps which will be exemplified in the formulations and processes hereinafter described and of which the scope of application will be indicated in the appended claims.

3 DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention embraces the use as a preservative for photographic developing agents in a silver halide developer, of polyquaternary ammonium bisulfites, sulfites and pyrosulfites of a certain restricted class defined by the general formula mentioned above, together with an alkali in an amount sufiicient to cause the pH of a developing bath to be at least 8. The term poly as used in the phrase polyquaternary ammonium bisulfites, sulfites and pyrosulfites denotes more than one and is not intended to denote solely a large number as poly is used in polymers. Actually, the term poly as employed herein indicates from 2 to 6 quaternary ammonium groups. The formula which embraces the polyquaternary ammonium compounds useful in the practice of the present invention is, as heretofore observed:

where R R R R R R R and R are selected from the class consisting of alkyls having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms, where Z is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers having from 1 to 3 carbon atoms in each alkylene, where Y is selected from the class consisting of H50 one-half SO and one-half S O and where n is an integer from to 4.

Exemplificative of such polyquaternary ammonium compounds are:

(1) 1,3 bis (trimethyl ammonium) 2 propanol bisulfite:

(2) N,N,N,N',N' N-hexamethy1 ethylene diammonium bisulfite Compound 2 is a member of a class of hexamethyl polyalkylene diammonium bisulfites all usable herein, the generic formula for such class being where n is an integer from 2 to 6;

(4) Hexarnethyl polymethylene diammonium bisulfites where R and R are selected from the class consisting of hydrogen and alkyls having from 1 to 4 carbon atoms and where n is an integer from 2 to 6;

N,N,N',N'-tetramethyl N,N-dihydroxyethyl ethylene diammonium bisulfite Compound 5 is a member of a class all usable herein, to wit,

(6) N,N,N',N' tetramethyl, N,N dihydroxyethyl alkylene diammonium bisulfite, where the alkylenes have from 1 to 6 carbon atoms.

All of the foregoing preservative compositions of the polyquaternary ammonium types are diquaternary ammonium compounds and can be generalized by the formula:

[a e-N 1, [E80,

where R R R R R and R are selected from the class consisting of alkyls-having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms and Where Z is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers of the formula:

( z)n z)n where n is an integer from 1 to 3.

An example of a triquaternary ammonium compound usable in the invention is:

(8) N,N',N" octamethyl diethylene triammonium triskis [bisulfite] It will be appreciated from inspection of the foregoing examples that they all fall within the scope of and are exemplificative of the generic formula for the class of polyquaternary ammonium compounds to which the present invention relates.

According to the invention the novel preservative and alkali are used (a) in working solutions of photographic developers, (b) in liquid developer concentrates, that is to say, liquid compositions which are intended to be diluted, as with water, to form Working solutions, (0) in liquid replenishers for developers, these constituting solutions more concentrated than working solutions and which are intended to be added to working solutions that are at least in part exhausted so as to bring them back to working strength, ((1) in combined developer/fixers of working strengths, these constituting so-called monobaths in Which both developing and fixing takes place, and (e) in monobath concentrates which are intended to be diluted, as with water, to form monobath working solutions.

The aforesaid novel preservative compounds of the present invention have the same stabilizing effect for photographic developing agents, to wit, inhibition of oxidation, in the presence of an alkali in an amount sufiicient to establish a pH of at least 8 for a developing bath and/ or monobath, as is conventionally supplied by alkali metal sulfites and/ or bisulfites, hydroxyalkylaminesulfur dioxide addition products and ascorbic acid and its isomers that are presently known in the art, and said novel preservative compounds employed in an alkaline aqueous medium having a pH of at least 8 are used pursuant to the present invention in the formulation of stable photographic developers, e.g. working solutions, replenishers and liquid concentrates, such developers being inclusive of a photographic developing agent and including conventional alkali-buffer systems such, for instance, as quaternary ammonium hydroxides, alkali metal carbonates, tetraborates, metaborates and hydroxides and the family of hydroxyalkylamines, either separately or in combination, in an amount sufficient to bring the pH of the developer to at least 8. Thus, the present invention embraces the use of the aforesaid novel preservative compounds in an alkaline aqueous solution having a pH of at least 8 for development of latent images in a silver halide gelatin layer where said compounds act as preservatives under the said alkaline condition in combination with all kinds of standard additives for other conventional purposes.

The present invention includes the use with the aforesaid novel preservative compounds in an alkaline aqueous medium of at least pH 8 of all conventional developing agents, particularly silver halide developing agents, which are well known to the art. An exemplificative partial list of photographic developing agents suitable for use, separately or in combination, with the new novel preservative compounds in alkaline aqueous working baths of at least pH 8, concentrates and replenishers, and Working monobaths of at least pH 8 includes: hydroquinone, chloro-hydroquinone, bromo-hydroquinone, p-phenylene diamine and its derivatives, n-monomethyl-p-aminophenol sulfate and 1-phenyl-3-pyrazolidone and its derivatives including 4,4-dimethyl-1-phenyl-3-pyrazolidone. Other conventional developing agents can be employed without altering the scope of this invention. Developers so formulated may contain the known photographic developer addenda, i.e., restrainers: viz. alkali metal chlorides, alkali metal bromides, alkali metal iodides; anti-foggants: viz. benzotriazole, S-methylbenzotriazole, 6-nitrobenzimidazole, 1-phenyl-5-mercapto tetrazole, Z-anthraquinone-sulfonic acid; sequestering agents: viz ethylenediamine tetraacetic acid and sodium hexametaphosphate; silver halide solvents: viz alkali metal thiosulfates and thioglycolates; various co-solvents: viz diethylene glycol; and gelatin hardening agents: viz formaldehyde and glutaraldehyde, as well as their bisulfite adducts.

It should be mentioned that developing compositions including photographic developing agents, are not restricted solely to use with gelatin layers. They may be employed equally well, for instance, in silver halide-containing gelatin layers including gelatin extenders, such as carboxymethylated soy protein, or succinoylated hydroxyethyl cellulose, which replace a part of the gelatin in the photographic emulsion layer.

It has been found by employing combinations of the foregoing constituents, to wit, the photographic developing agents, the novel preservative compounds, the alkalibutfer systems to obtain the minimum working bath pH mentioned, and, if desired, restrainers, anti-foggants, sequestering agents, silver halide solvents, co-solvents, and gelatin hardening agents, that high quality photographic developers and developer-fixers with excellent stability have been prepared.

It has been ascertained that by utilizing the present invention the novel preservatives mentioned above can be packaged and stored in highly concentrated liquid form. This is the result of the high degree of solubility of polyquaternary ammonium bisulfites, sulfites and pyrosulfites in water and particularly in the presence of an alkali in an amount sufficient to bring the aqueous medium to a pH of at least 8, such high degree of solubility being in comparison with the lesser solubility of conventional alkali metal sulfites and bisulfites and other prior art preservatives. The novel preservatives of the present invention prepared in high concentrated aqueous media are readily pourable into water with which they are quickly diluted upon moderate stirring to prepare working baths. The preservatives pour easily because they are of a medium viscosity in highly concentrated form. For example, where the novel preservatives are employed in a concentrate in a weight ratio of to 1 to water their viscosity in centipoises is in the order of from about 200 to about 300 Brookfield. It will be appreciated that such low order of viscosity for the concentrates of the developer and developer/fixer types embodying the present invention is particularly conducive to trouble-free mixing and is quite unlike some known concentrates of the developer and developer/fixer types employing as the developing agent preservative hydroxyalkylamine-sulfur dioxide addition products. These latter are considerably more viscous. For example, a developer concentrate containing an alkanolamine-sulfur dioxide addition product as the preservative in an amount of 25 g. per 50 ml. of developer concentrate along with proportionate amounts of developing agent and buffering agent has a viscosity of about 5250 centipoises Brookfield at room temperature. This obviously makes preparation of a working developer bath extremely difiicult and is quite unlike the instant concentrate employing the novel preservatives which, as noted, is particularly easy to mix without trouble in water and has a low viscosity. Moreover, the novel preservative of the present invention allows for greater developer system solubility, i.e. solubility of the system including a preservative and the developing agents and the hardener and/or anti-foggant and/or sequestrants and/or wetting agents and/or fixing agents, etc.

The novel preservative compounds of the present invention are highly compatible with the other constituents of the developing composition, i.e. are essentially inert thereto in the working bath. In particular, one of the advantages of employing any one or more of the novel preservatives of the present invention is that in combination with known gelatin hardening agents, namely, aldehydes and dialdehydes, a particularly stable working solution results.

It has been mentioned above that the novel preservative of the present invention can be used effectively in connection with aldehyde and dialdehyde gelatin hardening agents to form a particularly stable working developer or monobath solution. Specific aldehydes and dialdehydes useful in the present invention and mentioned by way of example are formaldehyde, glyoxal, glutaraldehyde, succinic dialdehyde, mal'eic dialdehyde, their derivatives and their bisulfite addition products.

The amount of novel preservative employed should be such that the preservative on an S0 basis is present in at least an equal molar ratio to the total number of mols of the developing agent or agents. The amount of alkali present should be sufficient so that in a developing bath and/or monobath the bath pH is at least 8 and preferably does not exceed 12 although the use of pHs from 12 to 14 is not excluded, such higher pHs under special circumstances being desirable.

The following examples will illustrate the use in accordance with the present invention of polyquaternary ammonium compounds in a variety of actual developer formulations including different types of systems in varying proportions sufiicient to act as a preservative for developing agents in an alkaline aqueous medium having a pH of at least 8.

Plus-X film and Kodabromide F-2 paper are processed at 68 F. in the developing bath of Example I for 2 minutes. Both materials are fixed in a rapid fixing bath for 3 minutes and washed for 15 minutes at 68 F. and then dried in the normal manner.

The following is a tabulation of gamma, fog base, and D-max. obtained with the above formulation and the conventional D-72 and D-76 developers published in the Photo Lab Index (Morgan and Morgan).

Kodabromlde F-2 paper Developer Fog time, Gamplus minutes 111a. base D-max Example I 2 2.30 0.00 1. 73 D72(dilutcd with2parts water). 1 1. 02 0.00 1.00

Plus-X film Example I 2 0.92 12 2. 24 D76 10 0. e .10 1.02

EXAMPLE II Water ml 700.00 N,N,N,N',N,N-hexamethyl ethylene diammonium bisulfite (preservative) gm 13.40 Ethylenediamine tetraacetic acid (sequestering agent) QTTI 2.00 Hydroquinone (developing agent) gm 3.00 l-phenyl-3-pyrazolidone (developing agent) gm 1.00 1-phenyl-5-mercapto-tetrazole (anti-foggant) gm-.. 0.02 2-methylaminoethanol (alkali-buffer) gm 23.20 Water to ml 1000.00 pH 10.18

This formulation will effectively develop photographic printing paper similar to Kodabromide at 68 F. for 1 minute. Fixing and washing is as described in Example I.

The following data was obtained from the above formulation:

Kodabromide F-2 paper Developer Fog time, Gamplus minutes Ina base Dmu Example II 1 1. 42 0.00 1.61 D-72 (diluted with 2 parts water) 1 1.62 0.00 1. 60

EXAMPLE III Water ml 600.00

Ethylenediamine tetraacetic acid (sequestering agent) gm 1.00

1,3 bis-[trimethyl ammonium] 2 propanol bisulfite (preservative) grn 58.00 Hydroquinone (developing agent) gm 20.00 Glutaraldehyde (50%) (hardener) gm 8.00

4 methyl 1 -phenyl-3-pyrazolidone (developing agent) gm 2.00 Benzotriazole (anti-foggant) gm 0.50 6 nitrobenzimidazole (anti-foggant) gm 0.20 Boric acid 1 gm 28.00 Potassium hydroxide (90%) gm 33.10 Potassium bromide (restrainer) gm 8.00 Water to ml 1500.00

Developer Fog time, Gamplus seconds ma base Drum:-

Example III 70 2. 30 0.33 3. 59 D-19 70 2. 21 0. 30 3. 30

The following is an example of a formulation based on a polyquaternary compound employed in a combined developer/fixer solution (monobath).

8 EXAMPLE IV Water ml 600.00 Ethylenediamine tetraacetic acid (sequestering agent) gm 2.00 N,N,N,N',N',N' hexamethyl ethylene diammonium bisulfite (preservative) gm 50.00 Hydroquinone (developing agent) gm-.. 10.00 1 phenyl 3 pyrazolidone (developing agent) m 2.50 Sodium thiosulfate (anhydrous) (silver halide solvent) gm 50.00 1 phenyl 5 mercapto tetrazole (antifoggant) gm 0.01 Sodium hydroxide (alkali) gm 20.00 Water to ml 1000.00 pH 11.50

The foregoing combined developer/fixer (monobath) will completely process film similar to Plus-X Pan in 8 minutes at 68 F. After processing, the film is washed for 5-10 minutes at 68 F. and dried.

This invention has been described in considerable detail with examples and references to specific formulations. It is understood that modifications and adjustments can easily be effected within the scope and spirit of this invention as described above and as defined in the following claims.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:

1. A method of developing an exposed gelatin-silver halide photographic emulsion layer comprising treating the emulsion layer with an aqueous bath including a developing agent, a polyquaternary ammonium preservative selected from the class consisting of polyquaternary ammonium bisulfite, sulfite and pyrosulfite having the forwhere R R R R R R R and R are selected from the class consisting of alkyls having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms, where Z is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers having from 1 to 3 carbon atoms in each alkylene, Where Y is selected from the class consisting of H50 one-half SO and one-half S O and where n is an integer from 0 to 4, and an alkali in an amount sufiicient to cause the bath to have a pH of at least 8, said preservative on an S0 basis being present in at least an equal molar ratio to the total number of mols of the developing agent.

2. A method as set forth in claim 1 wherein the developing agent is a compound selected from the class consisting of hydroquinone, chloro-hydroquinone, bromo-hydroquinone, p-phenylenediamine and its derivatives, nmonomethyl-p-aminophenol sulfate and 1-phenyl-3-pyrazolidone and its derivatives.

3. A method as set forth in claim 1 wherein the alkali is present in an amount to cause the bath to have a pH of between 8 and 12.

4. A method as set forth in claim 1 wherein the alkali is present in an amount to cause the bath to have a pH of between 8 and 14.

5. A method as set forth in claim 1 wherein the alkali is a compound selected from the class consisting of quaternary ammonium hydroxides, alkali metal carbonates, tetraborates, metaborates and hydroxides, and hydroxyalkylamines.

6. A method as set forth in claim 1 wherein the bath includes a silver halide solvent.

7. A method as set forth in claim 1 wherein the bath includes a gelatin hardener selected from the class consisting of aldehydes and dialdehydes.

8. A method as set forth in claim 1 wherein the bath is prepared by diluting in water a concentrate including a liquid preservative selected from said class.

9. A method as set forth in claim 1 wherein the preservative is 1,3-bis-[trimethyl ammonium]-2-propanol bisulfite.

10. A method as set forth in claim 1 wherein the preservative is N,N,N,N,N,N'-hexamethyl ethylene diammonium bisulfite.

11. A method as set forth in claim 1 wherein the preservative is N,N,N',N'-tetramethyl N,N-dihydroxyethyl ethylene diammonium bisulfite.

12. A method as set forth in claim 1 wherein the preservative is N,N,N,N-tetramethyl, N,N'-dihydroxyethyl alkylene diammonium bisulfite.

13. A method as set forth in claim 1 wherein the preservative is N,N,N"-octamethyl diethylene triammonium triskis [bisulfite].

14. An aqueous photographic developer for preparing a developing bath for an exposed gelatin-silver halide photographic emulsion layer, said developer including a developing agent, a polyquaternary ammonium preservative selected from the class consisting of polyquaternary ammonium bisulfite, sulfite and pyrosulfite having the formula R: is Rs where R R R R R R R and R are selected from the class consisting of alkyls having from 1 to 4 carbon atoms and hydroxyalkyls having from 2 to 4 carbon atoms, where X is selected from the class consisting of alkylenes having from 2 to 6 carbon atoms, hydroxyalkylenes having from 2 to 6 carbon atoms and dialkylene ethers having from 1 to 3 carbon atoms in each alkylene, where Y is selected from the class consisting of H80 one-half SO and one-half S O and where n is an integer from 0 to 4, and an alkali in an amount suflicient to cause the bath to have a pH of at least 8, said preservative on an 80;, basis being present in at least an equal molar ratio to the total number of mols of the developing hydroquinone, p-phenylenediamine and its derivatives, n-

monomethyl-p-aminophenol sulfate and 1-phenyl-3-pyrazolidone and its derivatives.

16. A developer as set forth in claim 14 wherein the alkali is present in an amount to cause the bath to have a pH of between 8 and 12.

17. A developer as set forth in claim 14 wherein the alkali is present in an amount to cause the bath to have a pH of between 8 and 14.

18. A developer as set forth in claim 14 wherein the alkali is a compound selected from the class consisting of quaternary ammonium hydroxide, alkali metal carbonates, tetraborates, metaborates and hydroxides and bydroxyalkylamines.

19. A developer as set forth in claim 14 which further includes a silver halide solvent.

20. A developer as set forth in claim 14 which further includes a gelatin hardener selected from the class consisting of aldehydes and dialdehydes.

21. A developer as set forth in claim 14 which is a liquid concentrate containing a high proportion of a preservative selected from said class.

22. A developer as set forth in claim 14 wherein the preservative is 1,3-bis-[trimethyl ammoniumJ-Z-propanol bisulfite.

23. A developer as set forth in claim 14 wherein the preservative is N,N,N,N',N,N'-hexamethyl ethylene diammonium bisulfite.

24. A developer as set forth in claim 14 wherein the preservative is N,N,N,N'-tetramethyl N,N'-dihydroxyethyl ethylene diammonium bisulfite.

25. A developer as set forth in claim 14 wherein the preservative is N,N,N,N'-tetramethyl, N,N'-dihydroxyethyl alkylene diammonium bisulfite.

26. A developer as set forth in claim 14 wherein the preservative is N,N, "-octamethyl diethylene triammonium triskis [bisulfite].

References Cited UNITED STATES PATENTS 2,944,898 7/1960 Beavers 96--66.4

3,017,270 l/1962 Tregillus 9661 M 3,549,370 12/1970 Sykes 96--66.4'

3,558,314 1/1971 Hueckstaedt 96-66.3

FOREIGN PATENTS 997,804 12/1964 Great Britain 96-66 NORMAN G. TORCHIN, Primary Examiner I. R. HIGHTOWER, Assistant Examiner US. Cl. X.R.

96--6l R, 61 M, 66 R CERTIFICATE OF CORRECTION Patent No. 3,705,806 December 12 l9' 72 I Donald J- y s, Harry Kroll and Theron R. Finch It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' Change the paragraph between the names and addresses of the inventors and the classification and number of claims to read as follows:

"Filed November '16, 1970, Serial No. 90,024".

Enigned and sealed this 1st day of May 1973.-

(SEAL) Attest:

' EDEiIARiBdi- FLE'lCHER, JR. ROBERT GOTTSCHALK Attesting Offlcer Commissioner of] Patents 

